"""``info()`` and ``features()`` helpers for the MacroLens unified API.

``info()`` returns a dict summarising the benchmark (name, version,
granularities, n_tickers, date range, per-task descriptions). All values
are read from :mod:`whatif_bench.config` and (when available) the
benchmark ``metadata.json`` written by the assembly pipeline; nothing
is hard-coded except the version constant and the per-task names /
predict shapes which are the contract documented in the design plan.

``features(granularity)`` returns ``{task: feature_names}`` by calling
the data layer for one ``test`` split per task and reading
``meta.attrs["feature_names"]``.
"""

from __future__ import annotations

import json
from typing import Any

from .. import config

__version__ = "0.2.0"

BENCHMARK_NAME = "MacroLens"

# Per-task descriptions. ``predict_shape`` is the contract documented in
# the unified-API design plan §1 (definitive) and §9 (coverage matrix);
# kept here because the methods package doesn't carry shape annotations
# directly on a task-by-task basis.
_TASKS: dict[str, dict[str, str]] = {
    "T1": {
        "name": "Time-Series Forecasting (TSF)",
        "predict_shape": "(N, horizon) float32",
        "target": "Close-price trajectory over the forecast horizon",
        "headline_metric": "mse",
    },
    "T2": {
        "name": "Public-Tail Equity Valuation (Val-PT)",
        "predict_shape": "(N,) float32",
        "target": "actual_market_cap",
        "headline_metric": "mape",
    },
    "T3": {
        "name": "Statement Generation (Stmt-Gen)",
        "predict_shape": "long-form DataFrame [ticker, fiscal_year, field, pred]",
        "target": "Per-field XBRL value",
        "headline_metric": "overall_mape",
    },
    "T4": {
        "name": "Scenario-Conditioned Return (Scen-Ret)",
        "predict_shape": "(N,) float32",
        "target": "Post-event return percentage",
        "headline_metric": "return_mae_pct",
    },
    "T5": {
        "name": "Private-Company Valuation (Val-Priv)",
        "predict_shape": "(N,) float32",
        "target": "actual_market_cap (price-derived inputs stripped)",
        "headline_metric": "mape",
    },
    "T6": {
        "name": "Generator Evaluation (Gen-Eval)",
        "predict_shape": "long-form DataFrame [ticker, fiscal_year, field, pred]",
        "target": "Per-field XBRL value (NL-only inputs)",
        "headline_metric": "overall_mape",
    },
    "T7": {
        "name": "Real-Estate Valuation (RE-Val)",
        "predict_shape": "DataFrame [address, pred_rent, pred_price]",
        "target": "Property rent and price",
        "headline_metric": "rent_MAPE",
    },
}

_GRANULARITIES = ("daily", "weekly", "monthly")


def _read_metadata_json(granularity: str) -> dict[str, Any]:
    """Read ``benchmark/<gran>/metadata.json`` if present, else return {}."""
    p = config.get_benchmark_dir(granularity) / "metadata.json"
    if not p.exists():
        return {}
    try:
        return json.loads(p.read_text())
    except json.JSONDecodeError:
        return {}


def info(granularity: str = "daily") -> dict[str, Any]:
    """Summarise the MacroLens benchmark at the requested granularity.

    Returns
    -------
    dict
        Keys: ``name, version, granularity, granularities, n_tickers,
        date_range, horizons, lookbacks, tasks``. ``date_range`` is a
        ``(start, end)`` tuple of ISO date strings.
    """
    md = _read_metadata_json(granularity)
    n_tickers = int(md.get("total_tickers", 0)) or None
    date_range_md = md.get("date_range") or {}
    start = str(date_range_md.get("start") or config.START_DATE)
    end = str(date_range_md.get("end") or config.END_DATE)

    return {
        "name": BENCHMARK_NAME,
        "version": __version__,
        "granularity": granularity,
        "granularities": list(_GRANULARITIES),
        "n_tickers": n_tickers,
        "date_range": (start, end),
        "horizons": list(config.get_horizons(granularity)),
        "lookbacks": list(config.get_lookback_windows(granularity)),
        "tasks": dict(_TASKS),
    }


def features(granularity: str = "daily") -> dict[str, list[str]]:
    """Return ``{task: feature_names}`` for every public task at *granularity*.

    Implementation note: we call ``ml.load(task, "test", granularity=...)``
    and read ``meta.attrs["feature_names"]``. T2/T3/T5/T6/T7 store column
    names; T1/T4 store the lookback-panel feature column names. Empty
    lists indicate the loader did not populate ``feature_names`` for the
    task.
    """
    # Local import to avoid a circular module-load between
    # ``macrolens.__init__`` and ``macrolens.meta`` -- ``data`` only depends
    # on ``dataloader``, so the deferred import is safe.
    from .data import load

    out: dict[str, list[str]] = {}
    for task in ("T1", "T2", "T3", "T4", "T5", "T6", "T7"):
        try:
            ld = load(task, "test", granularity=granularity)
        except Exception:
            out[task] = []
            continue
        feats = ld.meta.attrs.get("feature_names")
        if feats is None:
            out[task] = []
        else:
            out[task] = list(feats)
    return out


__all__ = ["info", "features", "__version__", "BENCHMARK_NAME"]